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Explanation of Tradebot Simulation |
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This simulation is loosely based on Robert
Axelrod's model of political actors. Any number of fiefdoms can be created
within a bounded territory. Two fiefdoms are picked at random: a "mean"
fiefdom and a "nice" fiefdom. The mean one must decide whether
to demand tribute from the nice one. If it does, the nice fiefdom may either
pay, or refuse to pay and face the consequences.
Each fiefdom has a size (i.e.: wealth) known only to it. In addition, every fiefdom keeps an estimate of the "meanness" of every other fiefdom. These estimates, called strategies, are set uniformly or randomly; they are updated as a result of events occurring during the game. Let us follow the major events during a single round of play. First, the game master designates the mean and nice fiefdoms. The mean fiefdom checks its internal strategy and asks if the "meanness" ranking of the of the nice fiefdom is more than .5 ("meanness" runs from 0 to 1). If so, it does not demand tribute. The mean fiefdom updates his strategy to a higher value. The nice fiefdom updates its internal strategy for the mean fiefdom to a lower value. On the other hand, the mean fiefdom might have recorded an internal strategy of less than .5. It would then demand tribute. If the nice fiefdom's strategy for the mean fiefdom were more than .5 it would pay. Otherwise, thinking the mean fiefdom was weak, the nice fiefdom would refuse. Both fiefdoms would then engage in a "war" which would continue until one third of the smallest fiefdom's resources were exhausted. At that time, the weaker fiefdom would surrender, and each side would update their internal strategy either upward (the loser's strategy of the winner) or downward (the winner's strategy of the loser). The size of the fiefdom is represented by the radius of circle drawn in the screen's active territory. Clicking before a run will create new fiefdoms. The "run" button starts the game; the results are seen immediately on the screen. If "Slow speed" is chosen then the mean and nice fiefdoms are shown in red and green, respectively. If either becomes bold (demands tribute or refuses to pay) then their color becomes brighter. In addition, certain run conditions are modifiable. If the internal strategies reasonably match the players' sizes then the game moves steadily to the conclusion of a single dominant fiefdom. However certain initial strategies may significantly deviate from actual sizes, thereby allowing small fiefdoms to "bluff" much larger fiefdoms out of existence. In some very strange cases, each surviving fiefdom believes (incorrectly) that one of the other fiefdoms is much stronger or weaker; the game continues in a state of relative equilibrium for a very long time. Future simulations will include distance (the mean fiefdom expends resources to bring the battle to the nice fiefdom), sunlight (fiefdoms can obtain wealth by growing things themselves as well as receiving tribute from others), the ability to change more parameters, and a method to extract digital summaries. In addition, we would like your suggestions and contributions. Please email them to Jim Bowlby. (prospero@best.com)
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